Acceleration = (change in speed) / (time for the change)
change in speed = (ending speed) - (starting speed)
change in speed = (10 m/s) - (2 m/s) = 8 m/s
Acceleration = (8 m/s) / (4 sec)
Acceleration = (8/4) (m/s²)
<em>Acceleration = 2 m/s²</em>
A circle has a revolution of 360°. Since there are 12 hour markings, each hour interval has an angle of 30°. In radians, that would be equal to π/6 radians. So, in every 1 hour that passes, it covers π/6 of an angle. So, the angular velocity denoted as ω is π/6 ÷ 1 hour = π/6 rad/h. We can compute the average linear velocity, v, from the relationship:
v = rω, where r is the radius of the circle which is the length of the hour hand
v = (2.4 cm)(π/6 rad/h)
v = 1.257 cm/hour
Therefore, the average velocity is 1.257 cm per hour.
For the average acceleration, it is equal to zero. The hands of the clock move at a constant velocity. Since acceleration is the change of velocity per unit time, there is no change of velocity because it's constant. That's why it is zero.
Distance between the two cars is increasing at the rate of 85 mph.
A passenger in Car-1 says that he is at rest in his own frame of reference,
and Car-2 is moving away from him at 85 mph, toward the west.
I believe the answer is A
